Sweet Smell of Renewable Fuel

Office of Science researchers borrowed from a fir tree to create a fuel that could leave diesel in the dust.

Commercial trucks in the U.S. burned approximately 22 billion gallons of diesel fuel in 2010. Replacing diesel with a clean, green and renewable biofuel could substantially reduce the industry’s carbon footprint.

One of the best parts of the season—next to presents of course!—is the hint of evergreen in the air. Yet the sweet smell doesn't last. It fades into forgotten corners, along with dusty sweets and unused gift cards.

But it doesn't have to be that way. In fact, researchers at the Office of Science's Joint BioEnergy Institute (JBEI) have discovered a way to keep a hint of evergreen all year. Thanks to the help of a friendly fir tree, they found a way to create a renewable alternative to diesel fuel.

Specifically, a team of JBEI researchers led by Taek Soon Lee, who directs JBEI's metabolic engineering program, used genetic engineering to create an advanced alternative to D2 diesel fuel, which is better known as "road diesel" since it is the form of diesel that powers trucks and cars. While most biodiesel fuels currently come from vegetable oil, the researchers at JBEI took a different track, and looked at a compound called bisabolane. Researchers hadn't considered using bisabolane before, since it is from a class of chemicals known as terpenes, which are used mostly in perfumes.

However, JBEI researchers demonstrated—for the first time—that bisabolane could serve as a true alternative to D2 diesel. They then tried to make it in the lab by taking a gene from an evergreen, a Grand Fir tree, and inserting it into two different microbes, yeast and E.coli. After a lot of effort, JBEI researchers eventually coaxed those microbes to produce a closely related compound that could easily be converted into the desired diesel substitute.

Trucks burned through some 22 billion gallons of diesel fuel last year, so any reduction via a renewable fuel would be a real increase for the environment. In addition to being renewable, the fuel JBEI developed is noncorrosive. And when used as a fuel additive, it is likely to provide superior performance for trucks operating in cold weather.

Admittedly, it may be a little while before JBEI's new fuel is available at local gas stations. That's because researchers estimate that the fuel will cost roughly $6 per gallon, which is more expensive than current D2 diesel. But cost reductions could come with improvements in the preparation process. And Dr. Lee and his colleagues are now preparing to scale up the bisabolane-making process at Berkeley Lab's Advanced Biofuels Process Demonstration Unit, a 15,000 square-foot state-of-the-art facility supported by DOE's Office of Energy Efficiency and Renewable Energy, which is designed to move advanced biofuels from the lab to the fueling station.

One day in the not-too-distant future, a massive diesel rig might fill up entirely on JBEI's renewable fuel. That'll represent an improvement for the environment thanks to researchers at the Office of Science. And it'll be a gift that lasts the year around; a gift of ever-green.